# of crows going to roost in Rockville, MD (trying to wrap my head around it)

[Andy Martin]

I was out this afternoon on west side of I-270, birding on the abandoned fire and police training facility in Gaithersburg on property between Great Seneca Hwy (Rt 119) and Rt. 28, Darnestown Rd. Crow spp. were constantly streaming overhead the whole hour. Coming from NW direction (assume portions of Mont Co Agricultural zone, southern Fred Co, maybe even Loudoun Co, VA?) and heading SE towards (again assumption here, toward the Rockville roost around Montrose Rd/old White Flint Mall area?). At one point, set my iPhone timer for 3 minutes and estimated 516 crows passing overhead in that time period.

516 divided by 3  min = 172/min. X 60 minutes would be 10,000+ crows/hr and they were still coming and going both before and after I got there. Is this possible? Know beside the Rockville roost, there is another crow roost in PG Co near New Carrolton Metro Station. Looking on Google Earth this would appear to be on approximately the same flight path as the Rockville roost. Could some of these crows be heading there as well? A double flock phenomenon? Weird observation but it was almost like there were two different flocks, some flying at much higher elevation than others. Fascinating!

Since I am a bird nerd, probably should stake out some position near beltway SE of Rockville area and see what is happening for myself.  :)

Andy Martin

Gaithersburg

[Haninah Levine]

Any chance they were circling around?

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[Andy Martin]

not that I could tell. All seemed to be making a beeline SE.

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[Paul O'Brien]

Andy,

The Crows that roost around the White Flint area have been going over my house in College Gardens for the past 50 years.  There is a steady stream for hours.  Back in the 70's, as I recall, Hal Weiringa estimated the roost at about 250,000 Crows.  It seems to be considerably fewer now, but still a large crowd of both American and Fish crows.  Incidentally, the Fish Crows are the first ones to begin going to the roost in the Fall and the last ones to stop using it in the Spring. 

Paul O'Brien

Rockville, MD     

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[JAMES SPEICHER]

On Wed, Nov 25, 2020 at 12:09 AM 'Paul O'Brien' via Maryland & DC Birding <mdbi...@googlegroups.com> wrote:
The Crows that roost around the White Flint area have been going over my house in College Gardens for the past 50 years.  There is a steady stream for hours.  Back in the 70's, as I recall, Hal Weiringa estimated the roost at about 250,000 Crows.  It seems to be considerably fewer now, but still a large crowd of both American and Fish crows.  Incidentally, the Fish Crows are the first ones to begin going to the roost in the Fall and the last ones to stop using it in the Spring.

************************
I can't go back that far, but the flight was quite a sight evenings waiting for the MARC train on the platform opposite the Rockville Metro Station in the late 1980s and subsequent years.  I wonder if West Nile virus had a hand in reducing the numbers.  That would have to have occurred sometime after 1999.

Jim S (NIH/West Nile virus vaccine researcher in an earlier life)

[Gail Mackiernan]

In the 1970s, the crow roost was in an extensive wooded area in back of what is now Pike and Rose Mall.  (At that time there was  just a small strip mall at the intersection of 355 and Montrose). I remember watching them come to roost back then, and there were tens of thousands, I could well believe a quarter-million. Mostly American Crows, Fish Crows were nowhere as common then in the area. The woods have been hacked at extensively, only a bit remains, so the roost has moved around in the area, and is now considerably smaller. Does anyone remember when the birds decided the upscale White Flint Mall was *the* place? It was literally like a scene out of The Birds!

Gail Mackiernan

Colesville

Sent from my iPad

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[Ann Hobbs]

Back in the early '90s  I worked in a building on Executive Blvd next to those woods.  It was a real spectacle seeing them fly in at night.  Needless to say, the crows were not popular with those who used the adjacent parking lot.

Ann Hobbs

Silver Spring

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[Steve Long]

When I worked in the tall tower building (USNRC) next to the White Flint Metro Station, it was interesting to be able to look out from the high floors and see crows in all directions as far as the eye could see, all apparently heading towards the White Flint Mall area  each evening.  There did not seem to be any circling involved, they were all coming in "as straight as a crow flies", literally.  I never even tried to estimate their total number, but I will easily accept that quarter million estimate.  And, this was after the West Nile Virus and avian flu episodes.  Even though that tower stuck up pretty much alone in the middle of lower buildings, we never seemed to get much in the way of bird strikes on the mostly glass exterior.  And I never heard of a crow strike on that building.

Steve Long

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[Andy Martin]

Appreciate the crow insight and history. 250,000 would have been something to see. Have lived in Montgomery since '67 but didn't start birding until '99 or '00, amazed that I was oblivious to such a gathering. My dad must have never made a Korvette's run with my brother and I at the right time and many a trip to the Jewish Community Center for winter swim meets must have been too early in the day. Even prebirding days, you would think I would have noticed this.

Thanks

Andy Martin

Gaithersburg

[Cheryl Hogue]

I began noticing the crow gathering when I worked in the little yellow schoolhouse at Randolph Road and Rockville Pike 1984-86.

For decades now, with a big blip for West Nile, they've streamed over my house near Holy Cross Hospital headed NW for the White Flint area each winter evening. That general area might be worth a closer look just for the sheer numbers, a really cool natural phenomenon happening in an urbanized area.

This historic site for the crows' gathering on winter evenings certainly has persisted, despite so much development.

Cheryl Hogue

Silver Spring